-- UTF-8 Encoding für deutsche Sonderzeichen sicherstellen
SET client_encoding = 'UTF8';

CREATE TABLE IF NOT EXISTS customers (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL,
    email TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS licenses (
    id SERIAL PRIMARY KEY,
    license_key TEXT UNIQUE NOT NULL,
    customer_id INTEGER REFERENCES customers(id),
    license_type TEXT NOT NULL,
    valid_from DATE NOT NULL,
    valid_until DATE NOT NULL,
    is_active BOOLEAN DEFAULT TRUE
);

CREATE TABLE IF NOT EXISTS sessions (
    id SERIAL PRIMARY KEY,
    license_id INTEGER REFERENCES licenses(id),
    session_id TEXT UNIQUE NOT NULL,
    ip_address TEXT,
    user_agent TEXT,
    started_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_heartbeat TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    ended_at TIMESTAMP,
    is_active BOOLEAN DEFAULT TRUE
);

-- Audit-Log-Tabelle für Änderungsprotokolle
CREATE TABLE IF NOT EXISTS audit_log (
    id SERIAL PRIMARY KEY,
    timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    username TEXT NOT NULL,
    action TEXT NOT NULL,
    entity_type TEXT NOT NULL,
    entity_id INTEGER,
    old_values JSONB,
    new_values JSONB,
    ip_address TEXT,
    user_agent TEXT,
    additional_info TEXT
);

-- Index für bessere Performance bei Abfragen
CREATE INDEX idx_audit_log_timestamp ON audit_log(timestamp DESC);
CREATE INDEX idx_audit_log_username ON audit_log(username);
CREATE INDEX idx_audit_log_entity ON audit_log(entity_type, entity_id);